刷题-Valid Palindrome 缺python

最新推荐文章于 2024-08-12 13:47:17 发布

原创最新推荐文章于 2024-08-12 13:47:17 发布 · 224 阅读

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文章标签：

#java #python

本文介绍了一种判断字符串是否为回文的方法，该方法只考虑字母数字字符并忽略大小写。通过双指针技巧，从字符串两端向中间比较字符来实现。文章包含了一个Java示例代码，展示了如何实现这一功能。

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.

For example,
"A man, a plan, a canal: Panama" is a palindrome.
"race a car" is not a palindrome.

Note:
Have you consider that the string might be empty? This is a good question to ask during an interview.

For the purpose of this problem, we define empty string as valid palindrome.

java：

public class Solution {
public boolean isPalindrome(String s) {
if (s == null){
return true;
}
else if (s.length()==0){
return true;
}
int i = 0;
int j = s.length()-1;
while (i<=j){
if (!AlNum(s.charAt(i))){
i++;
}
else if (!AlNum(s.charAt(j))){
j--;
}
else if (Character.toLowerCase(s.charAt(i)) == Character.toLowerCase(s.charAt(j))){
i++;
j--;
}
else{
return false;
}
}
return true;

}

public boolean AlNum(char abc){
if (abc >= 'a' && abc <= 'z'){
return true;
}
else if (abc >= 'A' && abc <= 'Z'){
return true;
}
else if (abc >= '0' && abc <= '9'){
return true;
}
else
{
return false;
}
}
}